﻿public class Person
{
    private string name;
    private int? age;

    public Person(string name)
    {
        this.name = name;
        this.age = null;
    }

    public Person(string name, int? age)
    {
        this.name = name;
        this.age = age;
    }

    public int? Age
    {
        get
        {
            return age;
        }
        set
        {
            age = value;
        }
    }

    public string Name
    {
        get
        {
            return name;
        }
        set
        {
            name = value;
        }
    }

    public override string ToString()
    {
        if (age.HasValue)
        {
            string toString = string.Format("{0} is {1} years old", name, age);
            return toString;
        }
        else
        {
            string toString = string.Format("{0} has no age specified", name);
            return toString;
        }
    }
}
